Nonvolatile semiconductor memories have the property of storing a charge while power is removed from the memory. Prior art devices, conventionally manufactured from silicon, generally have relatively slow write/clear operations because they require charge conduction through insulators, a process that limits lifetimes because of material damage. A typical prior art nonvolatile memory is described in S. M. Sze, Physics of Semiconductor Devices, 2nd Ed., John Wiley & Sons, 1981, pg. 496.
F. Capasso et al., "New Floating-Gate AlGaAs/GaAs Memory Devices . . . ", IEEE Electron Device Letters, Vol. 9, No. 8, August 1988, discloses a Type III/V floating gate memory. This memory differs significantly from the invention in that charge is put into and removed from the memory through a vertically displaced gate, rather than through the horizontal edges of a storage cell. Capasso also does not provide protection from ionizing radiation in the manner of the invention.